//\w字母，数字，下划线
let hd = "houdunren2012_@@";
console.log(hd.match(/\w+/g));
let email = "338493939@qq.com";
console.log(email.match(/^\w+@\w+\.\w+$/));
//用户名 a \w  5,10
/^[a-z]\w{4,9}$/;
